The present invention relates to a fossil fuel fired combustion apparatus and a method for operating the combustion apparatus for producing a carbon dioxide end product.
U.S. Pat. No. 5,175,995 to Pak et al describes a conventional power generation plant operable to burn fuel with air in a combustor so as to thereby provide combustion gas energy to drive a steam or gas turbine. In those versions of such conventional power generation plants which combust natural gas, petroleum fuel gas or coal gas as the fuel for the combustion process, this fuel includes carbon components such as carbon (C), carbon monoxide (CO), and other hydrocarbons (C.sub.m H.sub.n). Accordingly, the flue gas produced by a combustion process which combusts the fuel in the presence of air is comprised of carbon dioxide (CO.sub.2), nitrogen oxide (NO.sub.x), and sulphur oxide (SO.sub.x) as well as nitrogen gas (N.sub.2).
The '995 Pak et al patent further notes that the release of gases such as NO.sub.x, SO.sub.x, and CO.sub.2 into the atmosphere creates environmental pollution. Conventional power generation plants have conventionally countered such pollution by the deployment of removal equipment such as scrubbers to remove the NO.sub.x and SO.sub.x pollutants. Moreover, removal equipment has been deployed to remove the carbon dioxide (CO.sub.2) present in the flue gas including removal equipment of the type which utilizes a sorbent to selectively absorb the carbon dioxide (CO.sub.2) from the flue gas. However, this solvent approach, according to the '995 Pak et al patent, disadvantageously requires additional heat energy to heat the solvent and it is not practical to provide the relatively long contact time between the solvent and the carbon dioxide (CO.sub.2) for the solvent to fully absorb the carbon dioxide (CO.sub.2).
The '995 Pak et al patent discloses several versions of a closed combined cycle type power generation plant which purports to ameliorate some of the disadvantages of the carbon dioxide (CO.sub.2) absorbing solvent approach. In each version of the power generation plant disclosed in this reference, fuel is supplied to a combustor in the presence of oxygen instead of in the presence of air so as to produce a combustion gas (flue gas) which mainly includes a water component and carbon dioxide (CO.sub.2). This combustion gas is handled so as to separate the water component and the carbon dioxide (CO.sub.2) with the separated carbon dioxide (CO.sub.2) being recycled as the working fluid for driving a turbine of the combined cycle power generation plant. Since the combustion of the fuel in presence of oxygen instead of air substantially eliminates the creation of NO.sub.x and, further, since the carbon dioxide (CO.sub.2) is retained within the closed cycle as a working fluid, the approach disclosed by the '995 Pak et al patent advantageously avoids the discharge of NO.sub.x as well as carbon dioxide (CO.sub.2).
U.S. Pat. No. 4,498,289 to Osgersby also discloses a power system which combusts a hydrocarbonic fuel in the presence of oxygen in lieu of air so as to obtain a working fluid comprised of carbon dioxide (CO.sub.2). While the '995 Pak et al patent and the '289 Osgersby patent each disclose an arrangement for reducing carbon dioxide (CO.sub.2) emissions via the combustion of fuel in the presence of oxygen instead of air, the art could still benefit from an arrangement for new or existing power generation system designs which offers the flexibility to both to produce carbon dioxide (CO.sub.2) as a desirable end product and to use carbon dioxide (CO.sub.2) as support to the combustion process.